后张预应力摇摆墙动力耗能机制分析

Analysis of dynamic energy dissipation mechanism of post-tensioned prestressed rocking wall

摘要:

为分析后张预应力摇摆墙的墙-基摇摆碰撞冲击阻尼在地震动能量输入中的能量耗散贡献。基于ABAQUS建立摇摆墙精细化模型,结合模态分析确定摇摆墙结构动力特性,模拟发生大侧移下摇摆墙自由衰减振动,获得墙顶位移、速度和加速度动力时程响应,以摇摆墙恢复系数作为冲击阻尼量化指标,综合评价了不同高宽比和预应力水平摇摆墙的包含碰撞耗能多机制耗能能力。结果表明:所提出的模型能够精确还原摇摆墙试验模型的动力响应；高宽比对摇摆墙动力特性影响显著,减小高宽比可明显提高碰撞耗能占比,最高为78.3%；初始预应力水平对摇摆墙动力特性和自由衰减振动响应影响并不明显,但可显著提高耗能能力,将耗能占比提高至36.8%。

Abstract:

The energy dissipation contribution of wall-base rocking impact damping of post-tensioned prestressed rocking walls with ground motion energy input was analyzed. A refined finite element model of the rocking wall was established based on ABAQUS. The dynamic characteristics of the rocking wall structure was determined using modal analysis, and the free damping vibration of the rocking wall under large lateral displacement was simulated. The dynamic time history response of the wall top displacement, velocity, and acceleration was obtained. Taking the restitution coefficient of the rocking wall as a quantitative index of impact damping, the energy dissipation capacity of rocking walls with different aspect ratios and prestress levels was comprehensively evaluated, which contains multiple mechanisms of impact energy dissipation. Results show that the proposed model could accurately reflect the dynamic response of the rocking wall. The aspect ratio had great impact on the dynamic characteristics of the rocking wall. With the decrease in the aspect ratio, the proportion of impact energy dissipation increased significantly, up to 78.3%. The initial prestress level had no obvious influence on the dynamic characteristics and free damping vibration response of the rocking wall, but it significantly improved the energy dissipation capacity and increased the energy dissipation ratio to 36.8%.